What was one of the best Clippers offseasons ever just went terribly wrong.

Tuesday night, star power forward Elton Brand informed the Philadelphia 76ers that he would sign a five-year deal, worth an estimated $82 million dollars, despite the Clippers’ best, last-ditch efforts to keep him.

Just a few hours later, swingman Corey Maggette agreed to a deal with Golden State, though the exact amount of that deal wasn’t immediately known.

Two league sources told the Daily Breeze that by the end of negotiations with Brand, the Clippers had offered more than $80 million over five years.

“I don’t understand how this could’ve happened,” one source said. “It clearly wasn’t the money, because (the Clippers) came very close to what Philly offered.”

A message left by the Daily Breeze on Brand’s phone was not returned.

By moving to Philadelphia, Brand is closer to his hometown in upstate New York, back in the less-competitive Eastern Conference and able to join one of the up-and-coming young teams in the league.

Still, his decision came as a shock to the Clippers, who believed Brand would re-sign with the club up until late Monday night and did everything they could to keep him on Tuesday evening.

Brand, 29, is coming off an Achilles tendon injury, which sidelined him for all but eight games of last season. But the Clippers believed he was healthy and were committed to bringing him back. The former No. 1 overall draft pick had spent nine seasons with the Clippers and had grown into the face of the franchise.

Just a week ago, the Clippers had been dreaming of their newly constructed team, with Baron Davis running the point and Brand as the team’s cornerstone in the middle.

When Brand opted out of the final year of his contract on June 30, he said that he intended to return to the Clippers, but wanted to see if they could make a splash in the free-agent market.

Less than 24 hours later, the Clippers pulled off what was the biggest free-agent coup in their history by agreeing on a five-year, $65 million deal with Davis.

Brand, though, decided to listen to offers from other teams before committing to return. Golden State offered $90 million over five years last week. Philadelphia was interested, but could only offer $11 million a year.

Then on Tuesday, Philadelphia cleared an additional $2 million in salary-cap space by trading away Rodney Carney, Calvin Booth and a future No. 1 draft pick to Minnesota.

The Clippers tried to get close to matching that offer, but Brand decided on the 76ers.

As soon as Brand’s decision was known Tuesday night, the Clippers immediately dispatched a representative to reach out to Davis.

A message left by the Daily Breeze on Davis’ cell phone and his agent’s cell phone was not returned.

So what do the Clippers do next?

The good news is they have plenty of salary-cap space available to pursue other free agents now that Brand and Maggette are off the books and very little competition to drive up the bidding now that Philadelphia is committed to Brand.

Memphis is the only other team with comparable space, but it is not believed to be actively pursuing other free agents.

Reached on his cell phone Tuesday night, Clippers coach Mike Dunleavy did not want to comment on the Brand or Maggette situations, but said that he was encouraged by the financial commitment owner Donald Sterling had shown in the offers the team had made to Davis and Brand that totaled more than $140 million over the next 10 years.

A league source said that the Clippers would immediately make a push for Atlanta forward Josh Smith, but he is a restricted free agent and Atlanta can match any offer sheet he signs.